Dovetails – Chopping and Paring

I’ve been practicing my sawing, and I’m (finally) getting more comfortable with keeping the cut square to the face of the board on the tails, which is encouraging. As you can imagine, it’s just practice.

Since I had used up the last of my cheesy pine scraps on practicing sawing, I picked up two 1 x 10 pine boards at the big box store with the intention of making a small chest to store my saws in. This has been great dovetail practice, and I’m confident enough of my “prowess” that I’m certain I can make “paint grade dovetails” now. (read: they will at least fit together).

So I marked out and sawed the tails, and now I’m ready to chop out the waste between the tails, and saw out the half-pins on the ends of the tail boards. Let’s look at that first.

I made sure to get a nice deep cut with my marking gauge when marking out the baselines. The reason is that I wanted to make sure I had a clear, stable shoulder to use to pare to after clearing the bulk of the waste. When I sawed the half pin area I had the board turned so that the tails were to my left and tried to leave half of the baseline mark.

Using this shoulder as a guide I can pare away the waste with a sharp chisel. Tim recommended using a sideways slicing cut when doing this, and it really helps with controlling the cut. I tried to be super careful about staying above the baseline because a gap here will be really obvious. I think I did OK, the proof will be seeing how all the joints fit together.

Next it was time to deal with the waste between the tails. I’ve been using a coping saw to remove the waste, but I’m not satisfied with the results. The saw blade on my coping saw is slightly larger than the kerf left by my Lie-Nielsen saw, so I have to start a new kerf for the coping saw or risk gouging the sides of my tails.

I read in Christopher Schwarz’ blog about taking some of the set out of a coping saw blade, which seemed like a good idea. I used a coarse stone to dress both sides of the blade. I’d used this same approach to get my first dovetail saw to cut straight, so I had high hopes this would be a slam dunk.

In the end it turned out to be a mixed bag. The saw drops right into the kerf now, but removing some of the set really affected the blade’s ability to turn a sharp corner. Before, I could make a really sharp turn with the blade. After, the blade could only turn perhaps a 1/4″ radius at best. That meant the I still had to start my turn up high in the kerf, and still had to make two cuts per tail. Maybe I should have taken less set off of the blade? I’ll experiment more, but I’ve also ordered some coarse blades for my fret saw to see how that works for me. Rob Cosman recommends that approach, and it’s hard to argue with his results.

Since the saw was now difficult to turn I ended up having to stay pretty far above the baselines when sawing out the waste. It’s a little more chopping, but not a huge deal.

Before chopping out the waste, take a close look at your chisels. I’m using a set of Sandvik chisels that I’ve had for years — although in my power tool days they were just a shop decoration. They are comfortable to use, easy to sharpen and seem to hold an edge well. But they are lousy for dovetailing. Why? Look at the side view. That big vertical shoulder digs into the side of the tail and leaves a gouge that is visible in the finished joint. The chisel in the back is a Japanese dovetail chisel that has the edges beveled. It’s the only one I have, but I like the way it works. I may re-grind the sides of my Sandvik chisels, although I’m fairly tempted by the new Stanley chisels.

Here is how I’ve been approaching chopping the waste.

I chop the waste to within 1/16″ of the baseline at the most. I try to split the remaining waste with each placement of the chisel, taking a maximum bite of perhaps 3/16″. The rationale for removing the waste as close to the baseline as possible is that the waste will push the chisel back past the baseline. The chisel is a wedge, and Pine is really soft. It doesn’t take much to dent it. If you try to take too bik a bite when clearing the waste you run the risk of jamming it against the sides of the tail – which in this Big Box Pine (Squishius Cardboardius) will certainly damage the joint. I also only go half way through the wood, chopping from both sides.

Take moderate bites. I try to take half of the remaining waste with each roughing cut. If the space is particularly narrow or there is an excessive amount of waste I take a bit less to avoid jamming the waste against the shoulder of the tail.

I get a close to the baseline as I can before dropping my chisel into the baseline and chopping out the last bit of waste.

And be careful not to pry against the shoulder.

After chopping I carefully pare the bottom of the joint looking for any high spots. There is always some crumbs in the corners that needs to be removed. I don’t have a good picture of this, but what I do is to choke up on the chisel so that when I’m paring between the tails so that if it slips it can only go half way through the joint.

After cutting the tails on both boards for my saw chest I’m feeling more comfortable with the whole process. Cutting practice joints is all well and good, but cutting joints on an actual project feels great. Next, I’m onto the pins for the chest.

Joe, your sawing is coming along nicely, soft wood like SPF will compress so you can cut a little over size so when knocked together they will be gap free as long as the base line is straight.
Where did the drawing of the slicing cut method come from, I’d like to keep it for future use if it’s alright.

The drawing is from Hand Tools – Their Ways and Workings by Aldren Watson. I just got the book this week and have only thumbed through it, so I can’t tell how useful it will be. My first impression is good, it has lots of clear illustrations and show lots of operations that aren’t covered in any of my other books.